Joe, if you're working for an engineering firm and coming to a home inspectors forum for advice, on commercial and industrial applications, there is something wrong with the picture. Temperature control companies romance engineering firms all the time. This is how they get their equipment spec'd. Get to know them, make them buy you a nice lunch, and pick their brain. They will drive you to the job site, look at what you have and do a basic design build (they will let you have a taste but you won't get the recipe). I see that you're from the Atlanta, GA area. Give this guy a call: Mr. James Lee Padgett Services LLC 1400 Mountain Brook Drive Suite #100 Canton, Georgia 30115 (770) 345-6100 They are Mechanical Contractors in that area. James Lee use to be an area VP, with the Linc organization, and one of his accounts happened to be a company I worked for. He left Linc to go to Padgett. Whether or not he is still there is unknown as I haven't spoken to him since 2000. You gotta start making some commercial and industrial alliances.